High capacity conveyor trolley and method

ABSTRACT

An overhead conveyor, components therefor and method for making same, in which the conveyor trolley utilizes load wheels having double row bearings, and is designed for a channel having a height “X,” but is built with a maximum allowable load value which is equal to or greater than the maximum allowable load value for a trolley used in channels of height greater than X.

FIELD AND BACKGROUND OF THE INVENTION

The present application claims priority to U.S. Provisional application Ser. No. 61/747,172, filed Dec. 28, 2012, entitled HIGH CAPACITY CONVEYOR TROLLEY AND METHOD, and U.S. Provisional application Ser. No. 61/764,774, filed Feb. 14, 2013, entitled HIGH CAPACITY CONVEYOR TROLLEY AND METHOD.

The present invention relates to overhead conveyors, which typically comprise at least an “I-beam” track 1, trolleys 2 which have opposed wheels 3 engaging the bottom flanges of said I-beam track 1 on opposite sides of the center web of the beam, and a driven conveyor chain (not shown) connected to said trolleys at spaced intervals (FIG. 1). The chains usually comprise center links alternating with a pair of side links, which overlap the end of the center link on the opposite sides thereof, and are joined to the center link by a pin passing through the overlapping ends of the side links and center links. When the trolleys are thus driven by a chain, they are referred to as power trolleys.

While power trolleys are sometimes used directly to convey whatever items are being processed, they are more typically used to drive free trolleys 10, which travel freely on paired, laterally spaced load wheels 20 running on the lower flanges 41 of spaced inwardly facing “C” shaped tracks 40. Two horizontally oriented guide wheels 30 at the bottom of each free trolley are positioned between the C channel flanges 41, to help keep trolley 10 from shifting too far to the right or left as they travel in tracks 40.

The C channel tracks are supported by a pair of support arms 5, mounted atop the I-beam 1 and depending downwardly past either side thereof and past either side of the power trolleys. Downwardly depending pushers (not shown) are mounted on either the power trolleys 1 or the chain carried by and driving the power trolleys, for engaging dogs 11 on the free trolleys, to thereby move the free trolleys 10 along in their tracks 40. When it is desired to stop a trolley, mechanisms are provided for retracting either the pushers or the dogs 11, so that the trolley stops. The so called free trolleys thus carry the heavy loads which are to be moved from place to place. The trolley and “C” track arrangement can be used as powered trolleys driven by a drive chain. However, this arrangement is typically used as a set of free trolleys.

In accordance with long standing industry practice, trolleys are numbered in accordance with the approximate height of the I-beam or C channel tracks they are carried on. Industry standards, and longstanding industry practice call for 3 inch tracks, 4 inch tracks and 6 inch tracks. Thus, there have long been 3 inch trolleys, 4 inch trolleys and 6 inch trolleys.

Also by long recognized industry standards, the so called free trolleys (which can be driven) are built to carry heavier loads than the so-called driven trolleys. The free trolleys come in a standard grade and a heavier grade for carrying heavier loads. These loads are in accordance with long recognized standards. Thus the heavy load capacities for 3, 4 and 6 inch free trolleys are:

3 inch free trolley   800 # 4 inch free trolley 2,000 # 6 inch free trolley 4,000 #

SUMMARY OF THE INVENTION

The present invention comprises an overhead conveyor, components therefor and method for making same, in which the conveyor trolley is designed for a channel having a height “X,” but is built with a maximum allowable load value which is equal to or greater than the maximum allowable load value for a trolley used in channels of height greater than X. The trolley of the present invention utilizes load wheels having double row bearings.

This surprising departure from industry standards makes it possible to use, for example, four inch trolleys and four inch tracks, to care a load normally requiring six inch trolleys and six inch tracks.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a lateral cross sectional view of a prior art power and free trolley arrangement;

FIG. 2 is a lateral cross sectional view of a power and free trolley arrangement made in accordance with a preferred embodiment of the invention;

FIG. 3 is a side perspective view of a four inch trolley in accordance with the preferred embodiment, with the dog mechanism not shown;

FIG. 4 is a top plan view of view of a lour inch trolley in accordance with the preferred embodiment, with the dog mechanism not shown;

FIG. 5 is a lateral cross sectional view of double row bearing wheel for use as a load wheel in a preferred embodiment trolley;

FIG. 6 is a side elevational view of the wheel of FIG. 5;

FIG. 7 is an exploded cross sectional view of a double row bearing wheel for use as a load wheel in a preferred embodiment trolley.

FIG. 8 is a lateral cross sectional view of double row bearing wheel for use as a guide wheel in a preferred embodiment trolley.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Trolleys 10 a of the preferred embodiment comprises a pair of spaced side plates 50 a joined by bolts 51 a (FIGS. 3 and 4). A pair of load wheels 20 a are mounted to each side plate 50 a, facing outwardly from each side of trolley 10 a. Load wheels 20 a travel on the bottom flanges 41 a of channel shaped tracks 40 a (FIG. 2). Guide wheels 30 a are mounted on vertically oriented axels, located between side plates 50 a (FIGS. 2-4). Guide wheels 30 a project beyond side plates 50 a on each side of trolley 10 a, and have an outside diameter just slightly less than the space between the inwardly facing, spaced edges of the bottom flanges 41 a of opposed channel tracks 40 a. Dogs 11 a are retractable by a conventional mechanism, such that trolleys 10 a can be disengaged from pushers mounted on the power trolleys 2 or on the power chain carried by and driving the power trolleys 2.

Instead of a single row of bearing wheels conventionally used in conveyor trolleys, load wheels 20 a have a doable row of bearings 22 a and 22 b, positioned next to and parallel to one another within the confines of wheel 20 a (FIGS. 5 and 7). Bearings 22 a are located in the inside, or proximate row of bearings, that is the row facing a trolley side plate 50 a, while bearings 22 b are located in the outside, or distal row of bearings which faces away from a trolley side plate 50 a. This additional row of bearings significantly increases the overall load capacity of load wheel 20 a. Each wheel 20 a is formed on its interior to define an inwardly opening proximate outer race 21 a and an outwardly opening distal outer race 21 c, separated by a shared outer race wall 21 b. A proximate inner race defining ring 23 a and a distal inner race defining ring 23 b are inserted into wheel 20 a from opposite sides, so as to abut one another and trap the bearings 22 a between the inner races 23 a and b, and the outer races, 21 a and b, respectively. Inner race rings 23 a and b are carried on hub 27, which includes an inside lip 27 a, which locks proximate inner race 23 a in place when the components are assembled. A similar outer lip 27 b is then swaged on the outside edge of hub 27 to lock distal inner ring 23 b in place. The interior of hub 27 has a diameter to accept a wheel axel which is at least 25% greater than the standard ⅝ inch axel of prior art-trolley wheels, more preferably 50% greater (¾ to 1 inch in diameter). Hub covers 25 and 26 cover the opposite sides of each load wheel 20.

As can be seen by comparing the prior art trolley of FIG. 1 to the preferred embodiment trolley of FIG. 2, the outer tracking surface of each preferred embodiment load wheel is wider than the tracking surface on the prior art wheels on a correspondingly sized trolley. Specifically, FIG. 2 shows the preferred embodiment wheel tracking surface to be 100% wider than the tracking surface of prior art wheels on a correspondingly sized trolley.

The trolley wheels 22 a of the preferred embodiment are also preferably from 5 to 20%, more preferably from 10 to 15% less in mean outside diameter than the standard 2.4 inch diameter wheels used on 3 inch trolleys (i.e. 1.9-2.3, preferably 2.0-2.2 inches instead of 2.4), and the standard 3.2-3.3 inch diameter wheels used on the 4 inch (i.e. 2.5-3.0, preferably 2.7-2.9 inches) and the standard 4.0-5.25 inch wheels used on 6 inch trolleys (i.e. 3.2-3.8 inches, preferably 3.4-3.6 inches). The use of smaller outside diameter wheels is surprisingly made possible by the use of double row bearings. The decreased size of the load wheel allows for the use of smaller C-channels, saving significant materials.

The trolley guide wheels 30 a also preferably employ a double row of bearings 32 a and b, which significantly increase the overall load capacity of the wheel. (FIG. 8) For purposes of discussion, bearings 32 a are proximate, facing up toward the bottom of trolley 10 a. Bearings 31 b are distal, and will face down away irons the bottom of trolley 10 a, when the guide wheels are installed. The guide wheels 30 a axe of similar construction to the load wheels, except that the exterior of the guide wheel itself arcs outwardly slightly from side to side. In contrast, load wheels 22 a have generally flat outer surfaces, inclined slightly to match the incline of the track flanges 41 a on which they ride.

Each wheel 30 a is formed on it interior to define an inwardly opening proximate outer race 31 a and an outwardly opening distal outer race 31 b, separated by a shared outer race wall 31 c. A proximate inner race defining ring 33 a and a distal inner race defining ring 33 b are inserted into wheel 30 a from opposite sides, so as to abut one another and trap the bearings 32 a between the inner races 33 a and b, and the outer races, 31 a and b, respectively, inner race rings 33 a and b are carried on hub 37, which includes an inside lip 37 a, which locks proximate inner race 33 a in place when the components are assembled. A similar outer lip bob is then swaged on the outside edge of hub 37 to lock distal inner ring 33 b in place.

The two substantially parallel side-plates 50 a are connected preferably by at least grade 8 bolts 51 a, rather than by grade 5 bolts as are conventionally uses. These plates are preferably at least 15% thicker than prior art ⅜ inch thick trolley side-plates, and more preferably, at least 25% greater ( 7/16 to ½ of an inch).

In a preferred embodiment, the channel strengths as determined by pounds of material per foot of track, are 50-75% greater than standard strengths.

Trolley CEMA Strength Preferred Channel Standards Embodiment Strengths 3″ I-Beam 5.7 lbs/foot   8.5-10 lbs/foot 4″ I-Beam 7.7 lbs/foot 11.5-13.5 lbs/foot 6″ I-Beam 12.5 lbs/foot  18.7-21.8 lbs/foot 3″ C- 4.1 lbs/foot  6.1-7.2 lbs/foot Channel 4″ C- 5.4 lbs/foot  8.1-9.5 lbs/foot Channel 6″ C- 10.5 lbs/foot  15.7-18.4 lbs/foot Channel

The benefits of the present invention have not at ail been recognized or thought of by prior artisans. The use of at least double-row bearings in the load and guide wheels significantly increases the load capacity of the trolley without increasing the size of the trolley or track. This allows, for instance, loads traditionally carried only by a 6-inch trolley on a 6-inch track to be carried on a 4-inch track and trolley. Further reduction to the amount of materials needed for tracks is achieved by reducing the axial height of the load wheels.

For example, one 4 inch trolley has been load tested to 23,800 pounds without breakage. The preferred embodiment trolleys can he comfortably rated to twice the standard loads given for prior art trolleys of the same size:

Prior Art Load Preferred Embodiment Free Trolley Size Rating Load Rating 3 inch free trolley   800 # 1600# or higher 4 inch free trolley  2000 # 4000# or higher 6 inch free trolley 4,000 # 8000# or higher

Other embodiments of the invention are contemplated by the inventor. 

1. A conveyor trolley comprising: a body and a set of load wheels mounted on said body; said trolley body and said load wheels being dimensioned to be carried in a conveyor channel having a height “X,” but having an allowable load value which is equal to or greater than the maximum allowable load value for a trolley used in channels of height greater than X.
 2. The conveyor trolley of claim 1 comprising: said trolley load wheels having double row bearings.
 3. The conveyor trolley of claim 1 comprising: a 3 inch trolley having a load capacity of at least 1600 pounds.
 4. The conveyor trolley of claim 1 comprising: a 4 inch trolley having a load capacity of at least 4000 pounds.
 5. The conveyor trolley of claim 1 comprising: a 6 inch trolley having a load capacity of at least 8000 pounds.
 6. The conveyor trolley of claim 1 comprising: said load wheels having an outer tracking surface which is generally flat and inclined slightly to match the incline of the track flanges on which the load wheels will ride.
 7. The conveyor trolley of claim 6 comprising: each said load wheel having an outer tracking surface which is wider than the outer tracking surface on prior art wheels for a correspondingly sized trolley.
 8. The conveyor trolley of claim 6 in which said trolley body comprises two steel side-plates, each having a thickness of 7/16 to ½ of an inch.
 9. The conveyor trolley of claim 1 comprising: a 3 inch trolley having a wheel diameter of 2.0-2.2
 10. The conveyor trolley of claim 1 comprising: a 4 inch trolley having a wheel diameter of 2.7-2.9 inches.
 11. The conveyor trolley of claim 1 comprising: a 6 inch trolley having a wheel diameter of 3.2-3.8 inches.
 12. A conveyor trolley comprising: a body and a set of load wheels mounted on said body; each of said load wheels having a double row of bearings positioned next to and parallel to one another within the confines of said load wheel; and said load wheels having an outer tracking surface which is flat and inclined slightly to match the incline of the track flanges on which the load wheels will ride.
 13. The conveyor trolley of claim 12 comprising: each said load wheel having an outer tracking surface which is wider than the outer tracking surface on prior art wheels for a correspondingly sized trolley.
 14. The conveyor trolley of claim 13 comprising: a 3 inch trolley having a wheel diameter of 2.0-2.2 inches.
 15. The conveyor trolley of claim 13 comprising: a 4 inch trolley having a wheel diameter of 2.7-2.9 inches.
 16. The conveyor trolley of claim 13 comprising: a 6 inch trolley having a wheel diameter of 3.2-3.8 inches.
 17. The conveyor trolley of claim 12 comprising: a 3 inch trolley having a wheel diameter of 1.9-2.3.
 18. The conveyor trolley of claim 12 comprising: a 4 inch trolley having a wheel diameter of 2.5-3.0 inches.
 19. The conveyor trolley of claim 12 comprising: a 6 inch trolley having a wheel diameter of 3.2-3.8 inches.
 20. The conveyor trolley of claim 12 in which said trolley body comprises two steel side-plates, each having a thickness of 7/16 to ½ of an inch.
 21. An overhead conveyor comprising: a trolley having a body and a set of load wheels mounted on said body; said trolley body and said load wheels being dimensioned to be carried in a conveyor channel having a height “X,” but having an allowable load value which is equal to or greater than the maximum allowable load value for a trolley used in channels of height greater than X; and a channel for carrying said trolley, wherein the channel strength as determined by pounds of material per foot of track, are 50-75% greater than standard CEMA strengths for a channel of height X, as set forth in the table below: Trolley CEMA Strength Claimed Channel Standards Strengths 3″ I-Beam 5.7 lbs/foot   8.5-10 lbs/foot 4″ I-Beam 7.7 lbs/foot 11.5-13.5 lbs/foot 6″ I-Beam 12.5 lbs/foot  18.7-21.8 lbs/foot 3″ C-Channel 4.1 lbs/foot  6.1-7.2 lbs/foot 4″ C-Channel 5.4 lbs/foot  8.1-9.5 lbs/foot 6″ C-Channel 10.5 lbs/foot  15.7-18.4 lbs/foot


22. The conveyor trolley of claim 21 comprising: said trolley load wheels having doable row bearings.
 23. The conveyor trolley of claim 22 comprising: said load wheels having an outer tracking surface which is generally flat and inclined slightly to match the incline of the track flanges on which the load wheels will ride.
 24. The conveyor trolley of claim 23 comprising: each said load wheel having an outer tracking surface which is wider than the outer tracking surface on prior art wheels for a correspondingly sized trolley.
 25. The conveyor trolley of claim 24 comprising: axels on said load wheels of ¾ to 1 inch in diameter. 